Sustainable Use of Citrus Waste as Organic Amendment in Orange Orchards

The use of citrus waste (peel, CW) as organic fertilizer was investigated on soil microbiota and on soil physico-chemical and hydraulic characteristics. The biotic components on CW and the effect on nutritional status, leaf chlorophyll content, fruit set and production of “Tarocco” orange trees were also identified. The citrus waste was supplied to an experimental orchard at different doses: 45 kg m−2 (with and without Ca(OH)2 addition) and 90 kg m−2. The study was conducted in three consecutive years (2015–2017) on 20-year old orange trees at the experimental farm of the University of Catania (Italy). The main results of the study confirm that the use of CW as a biofertilizer offers a great opportunity for sustainable sweet orange production.